Reciprocating Saw Blade Tooth Pattern for Burr Reduction

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Solution Overview

Problem

Prior art reciprocating saw blades with negative rake angles often generate excessive burrs when cutting metal workpieces, which are undesirable and require additional effort and expense to deburr, while also not providing the desired blade life.

Innovation Solution

A reciprocating saw blade design featuring a repeating pattern of cutting teeth with a leading tooth having a negative rake angle and trailing teeth with less negative or positive rake angles, reducing burr formation and enhancing blade life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If negative rake angles are employed on cutting teeth to make the blade robust and improve blade life, then blade life is improved, but excessive burrs or burrs of excessive size are generated when cutting metal work pieces

Engineering Contradiction:
Improveblade lifeVSAvoidburr generation
Core Design Contradiction:
Duration of action of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The cutting teeth are segmented into two distinct types within a repeating pattern: leading teeth with negative rake angles for robustness and blade life, and trailing teeth with less negative or positive rake angles for clean cutting. This segmentation allows each tooth type to perform its specific function optimally without compromise.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different rake angles are applied to different positions of teeth along the cutting edge. Leading teeth have more negative rake angles optimized for durability, while trailing teeth have less negative or positive rake angles optimized for burr-free cutting. This local differentiation of tooth properties resolves the contradiction between blade life and burr generation.

Inventive Principle:
Principle #3Local quality

2Duration of action of stationary object

If negative rake angles are used to enhance blade robustness, then blade life is extended, but additional effort and expense are required for deburring metal work pieces

Engineering Contradiction:
Improveblade lifeVSAvoiddeburring time
Core Design Contradiction:
Duration of action of stationary objectVSLoss of time

Solution Approach 1:

The cutting teeth are segmented into two distinct types within a repeating pattern: leading teeth with negative rake angles for robustness and blade life, and trailing teeth with less negative or positive rake angles for clean cutting. This segmentation allows each tooth type to perform its specific function optimally without compromise.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The trailing teeth with less negative or positive rake angles convert the potential harm of burr generation into a benefit by producing clean, burr-free cuts. This eliminates the need for additional deburring operations, saving time and expense while maintaining the blade life benefits of negative rake angles in the leading teeth.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Duration of action of stationary object

If all teeth have negative rake angles for robustness, then blade life is improved, but cutting efficiency and surface finish deteriorate

Engineering Contradiction:
Improveblade lifeVSAvoidcutting efficiency
Core Design Contradiction:
Duration of action of stationary objectVSProductivity

Solution Approach 1:

The cutting teeth are segmented into two distinct types within a repeating pattern: leading teeth with negative rake angles for robustness and blade life, and trailing teeth with less negative or positive rake angles for clean cutting. This segmentation allows each tooth type to perform its specific function optimally without compromise.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different rake angles are applied to different positions of teeth along the cutting edge. Leading teeth have more negative rake angles optimized for durability, while trailing teeth have less negative or positive rake angles optimized for burr-free cutting.

Inventive Principle:
Principle #3Local quality

4Duration of action of stationary object

If all teeth have negative rake angles for robustness, then blade life is improved, but surface finish quality deteriorates

Engineering Contradiction:
Improveblade lifeVSAvoidsurface finish quality
Core Design Contradiction:
Duration of action of stationary objectVSManufacturing precision

Solution Approach 1:

The cutting teeth are segmented into two distinct types within a repeating pattern: leading teeth with negative rake angles for robustness and blade life, and trailing teeth with less negative or positive rake angles for clean cutting. This segmentation allows each tooth type to perform its specific function optimally without compromise.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different rake angles are applied to different positions of teeth along the cutting edge. Leading teeth have more negative rake angles optimized for durability, while trailing teeth have less negative or positive rake angles optimized for burr-free cutting.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS11583945B2Recip blade
Publication Date: 2023.02.21 BLACK & DECKER CORP
  • US11583945B2 patent drawing
  • US11583945B2 patent drawing
  • US11583945B2 patent drawing

AI summary

A recip blade has a cutting edge defining a cutting direction and a repeating pattern of cutting teeth. Each repeating pattern includes (i) a leading tooth with respect to the cutting direction that includes a rake face defining a first rake angle that is negative, and (ii) a trailing tooth following the leading tooth with respect to the cutting direction that includes a rake face defining a second rake angle that is less negative than the first rake angle.